10 Things You Need to Know for Thursday

Your daily look at late-breaking news, upcoming events and the stories that will be talked about Thursday:

1. TEEN WIELDING KNIVES SLASHES, STABS CLASSMATES. A 16-year-old boy with a “blank expression” injures 21 students and a security guard in the crowded halls of his suburban Pittsburgh high school.

2. WHAT ECONOMIC THREAT BY MOSCOW MIGHT SIGNAL. Putin’s latest tactic suggests he may be aiming to secure Russia’s clout with Ukraine without invading.

3. MORE PINGS RENEW HOPE OF FINDING MH370. The leader of the search says he believes crews are closing in on the “final resting place” of the missing Malaysian jetliner.

4. CAR SMASHES INTO FLORIDA DAY CARE. A child dies and 14 others are injured in the hit-and-run, chain-reaction crash.

5. INTERNET SECURITY LAPSE UNDETECTED FOR YEARS. Millions of passwords, credit card numbers and other sensitive information have been potentially vulnerable to hackers.

6. AFGHANS BEGIN PROBE OF AP PHOTOGRAPHER’S DEATH. The alleged gunman is being held in Kabul in a rare instance of a possible perpetrator of an insider shooting being captured alive.

7. WHERE TUMBLING TUMBLEWEEDS ARE CAUSING HEADACHES. The plants are rolling across the drought-stricken prairie of southern Colorado, blocking roads and briefly barricading homes and an elementary school.

8. MORE RECALLS OVER SAFETY CONCERNS. Toyota is recalling nearly 1.8 million vehicles in the U.S. for various problems, including air bags that may fail to deploy.

9. NEW-FANGLED HUMAN HEART ON HORIZON. Researchers predict they’ll be able to build an artificial heart with a 3-D printer in three to five years.

10. WHO STRUGGLES WITH FEDERAL TAX RETURNS. Not many. According to an AP-GfK poll, 90 percent of taxpayers use either a preparer or software and the majority say filing is easy.